Boom-mounted rotary-wheel trench excavator

ABSTRACT

A vehicle supported by caterpillar tracks has an outrigger arm carrying a rotatable drum with its axis slightly inclined to the direction of travel so that a front face of the drum, equipped with an array of cutting blades, bites into the soil to dig a trench as the vehicle moves forward. A conveyor belt extends at an acute angle into the open rear face of the drum to carry off detached clods while a retractable stop projects inwardly from the drum periphery to entrain larger fragments toward a scraper disposed above the belt within the drum.

United States Patent Beslin et al.

[54] BOOM-MOUNTED ROTARY-WHEEL TRENCH EXCAVATOR [72] Inventors: Dragoliub Beslin; Benko Beherano, both of Zemun; Radivoj Mirkovic, Belgrade, all of Yugoslavia [73] Assignee: Strojna Tovama Trbovlje, Trovlje, Yu-

goslavia [22] Filed: Sept. 2, 1969 211 Appl. No.: 854,657

[52] US. CL... ..37/9l,37/l90 51 1 Int. Cl. 5s FieldofSearch ..37/70,l89,l90,9l-97 [56] References Cited UNITED STATES PATENTS 306,580 l0/l884 Chaguette f. ..37/70 719,567 2/1903 Conlin ..37/70 Feb. 29, 1972 1,310,728 7/1919 Alchevsky ..37/93 2,032,911 3/1936 Brown 3,260,345 7/ 1966 Scholler 3,340,627 9/1967 Mittry, Jr. et al. ..37/93 Primary Examiner Robert E. Pulfrey Assistant Examiner--Clifford D. Crowder Attorney-Karl F. Ross [57] ABSTRACT A vehicle supported by caterpillar tracks has an outrigger arm carrying a rotatable drum with its axis slightly inclined to the direction of travel so that a front face of the drum, equipped with an array of cutting blades, bites into the soil to dig a trench as the vehicle moves forward. A conveyor belt extends at an acute angle into the open rear face of the drum to carry off detached clods while a retractable stop projects inwardly from the drum periphery to entrain larger fragments toward a scraper disposed above the belt within the drum.

11 Claims, 7 Drawing Figures Patented Feb. 29, 1972 3,645,020

2 Sheets-Sheet l 7 Dragoljub Be /in Ben/ 0 Beher'ano Attorney Rad/v Mirkovic Patented Feb. 29, 1972 3,645,020

2 Sheets-Sheet 2 Dragoljub Bei'lin Benko Beherano Radivqj Mirkovic INVENTORS.

ad Kw Attorney BOOM-MOUNTED ROTARY-WHEEL TRENCII EXCAVATOR Our present invention relates to a trench excavator.

The general object of this invention is to provide a machine adapted to dig trenches of substantially uniform cross section throughout their length, e.g., for irrigation purposes, and to do so in an expeditious and efficient way.

A more particular object is to provide a machine of this type which can be readily adjusted, within certain limits, to different depths and/or width of trenches to be dug.

It is also an object of our invention to provide means in such a machine for depositing the excavated soil in an orderly manner at a location remote from the freshly dug trench, advantageously in the wake of a vehicle supporting the excavator proper.

Mechanical excavators satisfying these requirements to a limited extent are already known, e.g., from German Pat. No. 1,139,074. In contradistinction to conventional systems of the bagger type, utilizing scoops on the circumference of an excavating wheel, the device according to our invention comprises a drum joumaled on a free end of an outrigger arm extending laterally from a supporting vehicle, this drum being rotatable in a plane generally perpendicular to the direction of locomotion of the vehicle and being provided with cutterspreferably several generally radial cutter arrays-for digging a I ditch upon a lowering of the bottom part of the drum into the soil while the vehicle advances. Fragments detached by the cutters enter the drum through an apertured front wall thereof and are directed onto a conveyor extending from behind into the drum to carry these fragments to a distant point further to the rear and away from the ditch just dug.

Since ditches or trenches generally need not have a geometrically exact part-circular profile, the width of the trench can be somewhat altered--with its depth remaining constant-by varying the angle of inclination of the drum axis to the direction of travel. With this angle ranging up to about 15, and with its vertex lying to the rear of the excavator assembly so that the drum axis diverges forwardly from the direction of travel, the conveyor can be an endless belt rising rearwardly from the level of the drum axis and including an acute angle of, say, 30 to 60 with that axis in the horizontal plane. A tiltable beam, forming part of the outrigger arm, advantageously has a bifurcate end with a first prong forming a cantilever bearing for the drum and a second prong supporting the belt and other, stationary elements adjacent the open rear drum surface to serve as guides for the loose soil fragments to be directed onto the conveyor. These elements may include a cowl overlying the upper reach of the conveyor belt at its receiving end and opening into the interior of the drum in a direction facing oncoming soil fragments entrained on the inner drum periphery. The cowl advantageously carries a scraper to detach these fragments from the inner drum periphery substantially at the zenith thereof, causing them to fall onto the conveyor.

With suitable selection of the rotative speed of the drum,

the centrifugal force developed by the loose fragments may be given such a value as substantially to balance the force of gravity at the zenith of the drum periphery so that the clods can be easily removed by the scraper. According to a further feature of our invention, the clods are more positively entrained by one or more stops projecting inwardly from the drum periphery, these stops being retractable by a stationarycam or equivalent mechanism on approaching the zenith in order to avoid a collision with the scraper.

The above and other features of our invention will be described hereinafter in greater detail with reference to the accompanying drawing in which:

FIG. 1 is a front view of a trench excavator accordingto our invention during operation;

FIG. 2 is a top view of the excavator shown in FIG. 1;

FIG. 3 is an enlarged front view of a drum forming part of the excavator of FIGS. 1 and 2;

FIG. 4 is a rear view of the excavator drum with part of an associated conveyor;

FIG. 5 is a cross-sectionalview of the excavator drum, showing part of the conveyor;

FIG. 6 is a cross-sectional detail view of a blade fitted to the drum, taken along the line VI-VI of FIG. 3; and

FIG. 7 is an axonometric view of a retractable stop on excavator drum.

FIGS. 1 and 2 show a self-propelled tractor-type vehicle the having an operators cab 10 with an engine 10a supported by.

caterpillar tracks 11, via a turret 9, to move over the terrain on a path parallel to a ditch 16 to be excavated. The cab 10- has a laterally extending outrigger arm generally designated 5, with a short fixed portion 52 on turret 9 to which a moveable portion 51 in the form of a bifurcate beam is articulated at 8 for swinging in a vertical plane under the control of the operator via a draw rod 81. A prong 514 of this beam carries a rotatable cutting drum 1 with its axis slightly inclined to the.

direction of travel, i.e., diverging forwardly from that direction at an acute angle of up to about l5 in a horizontal plane. The cutting drum 1 comprises a sheet-metal rim consisting of two frustoconical parts, i.e., a rear part 101 and a.

front part 102, interconnected at their larger bases by a cylindical middle part 103.

Front part 102 is integral with several (here three) angularly equispaced, generally radial sheet-metal strips 2 which span the otherwise open front of the drum and form a mounting for its hub. Each band is provided, at progressive distances from the center,-with a multiplicity of transverse slots 21a bounded along its outer edge by a sloping shelf 21 (best seen in FIG. 6)- which serves as a support for a cutter blade 21b overhanging the slot. The strips 2 are slightly curved so that the edges of blades 21b include an obtuse angle with the radial direction and point generally forwardly in the direction of rotation indicated by arrows A, FIGS. 2 and 3. At the junction of each strip 2 with peripheral zone 102, two relatively inclined slots' meet to form a V-slot 22a with a forwardly pointing vertex on the circumference of the smaller base of that frustoconical zone; A V-shaped shelf 22 bounds the trailing edge of slot 224 and supports a generally triangular double-edged blade 22b. The last blade 23b of the series straddling the junction of annular zones 102, 103 is of similar wedge shape and projects beyond the circular outline of the drum. The latter is set in rotation by a motor 12 in cab 10 via a Cardan shaft 13 terminating at a speed reducer 14 to which the drum shaft journaled in prong 514 is coupled; shaft 13 has two sections 131, 132 interconnected by a universal joint 133.

The second prong 515 of the forked beam 51 supports a stationary apron 104 which covers the lower half of the otherwise open rear surface of drum 1 beneath a conveyor, generally designated 6, having a preferably tubular supporting bar 61 pivoted at 513 to prong 515 so as to be swingable between its illustrated operating position (FIG. 2) and a retracted position alongside the beam 51. Two pairs of spring clips 511, 512, projecting rearwardly from beam 51 on opposite sides of fulcrum 513, resiliently grip the bar 61 in its operative position and its retracted position, respectively. In its operative position the end of conveyor 6 remote from cab 10 enters the drum 1 from behind so as to come to rest below the zenith of the inner drum periphery. Bar 61 carries a set of horizontal supporting rollers 62, flanked by pairs of slightly inclined retaining rollers 61', for the guidance of an endless'resilient belt 64 (e.g., of rubber) wound under tension around an end roller 63 at the front end and a similar roller 63' at the rear end of :conveyor 6. Either or both of these end rollers may be driven, by conventional means not shown, to move the belt 64 in the direction indicated by the arrow B in FIG. 2.

Also supported on the free end of prong 515 of the trusslike beam 51 is a cowl 6S overlying the extremity of conveyor 6 when the latter is operatively positioned to enter the drum 1. The open 'end of the cowl, confronting the ascending upper quadrant of the drum, carries a scraper 7 of trapezoidal profile hugging the inner drum surface; cowl 65 is also supported by prong 514 via a counterbearing on the inner hub of drum 1.

As illustrated in FIG. 7, drum 1 is provided along its cylindrical peripheral zone 103 with one or more retractable stops 3 for entrainment of soil fragments in its interior to the region of scraper 7. The stop 3 seen in FIG. 7 comprises an elbowshaped lever pivoted on the outer drum surface to a pair of lugs 31 and terminating in a fin 35 which normally projects radially inward through a slot 32 in the drum periphery. A leaf spring 33 anchored to the drum bears upon the lever 3 to urge the fin 35 inwardly. A finger 34 rigid with that lever rides up a stationary cam 4, carried near the top of the drum in its interior via an arm 41 forming part of the beam-supported fixed structure, whenever the stop 3 approaches the zenith whereby the fin 35 is outwardly retracted into its inoperative position shown in FIG. 7 so as not to strike the scraper 7. This action also releases any entrained clods which can thus be readily stripped off by the scraper. Owing to the presence of cowl 65 and apron 104, these soil fragments cannot fall through the drum onto the floor of the freshly dug trench 16.

The excavator according to our invention, operating continuously, cuts a clean face nearly perpendicular to the direction of locomotion into the receding end of the ditch as the vehicle 10, 11 advances in the direction of arrow C (HO. 2). By steering the vehicle along a straight, curved or meandering path, the operator may impart any desired configuration to the ditch being dug. The smoothly curved trench wall prevents undesirable accumulations of rain water and insures a smooth flow when the ditch is to be used for irrigation purposes. The device can also be used to clean and reshape a ditch during maintenance work. The depth of the ditch is determined by the extent to which the drum 1 is lowered into the soil with the aid of rod 81. When traveling to and from the work site, the operator retracts the rod 81 to lift the drum 1 above the terrain and, preferably, also swings the conveyor 6 into its idle position alongside outrigger arm 5. This can be done by suitable servomotors, not shown, which could also be used to change the azimuthal position of arm 5 through rotation of turret 9. Such horizontal swingingpf the arm may be used during excavating operations to modify the orientation of the drum faces with reference to the direction of locomotion C, possibly with an increase in the relative inclination of the drum axis to more than its normal angle (e.g., included with that direction when the arm 5 is perpendicular to the caterpillar tracks 11. For road travel, the arm 5 and the conveyor 6 may be swung into substantial alignment with the caterpillar tracks so that the effective width of the vehicle is minimized.

The camming mechanism illustrated in FIG. 7 is representative of a variety of mechanical, hydraulic, electromagnetic or other systems for periodically retracting the stop 3 in the rhythm of drum rotation. The aforementioned servomotors can also be actuated by electric, hydraulic or pneumatic means.

We claim:

1. A trench excavator comprising:

a vehicle movable in a predetermined direction, said vehicle being provided with a laterally extending outrigger arm;

a drum joumaled on a free end of said arm for rotation in a plane generally perpendicular to said direction, said drum having an apertured front surface externally provided with cutter means, an open rear surface and a substantially continuous peripheral zone between'said surfaces; drive means for rotating said drum; conveyor means extending through said open rear surface into said drum for carrying ofi soil fragments; and retractable stop means on said peripheral zone radially movable between an inwardly projecting position for the rotary entrainment of soil fragments detached by said cutter means and an outwardly withdrawn position for releasing such soil fragments onto said conveyor means. 2. A trench excavator as defined in claim 1 wherein the axis of said drum diverges forwardly from said direction at an acute angle of up to substantial] 15.

. A trench excavator as de med in claim 1 wherein said arm is provided with supporting means for said conveyor means, the latter including an endless belt extending to the rear of said vehicle at an acute angle to said arm in an operative position of said conveyor means.

4. At trench excavator as defined in claim 3 wherein said conveyor means further comprises a roller-carrying bar enveloped by said-belt, said supporting means including a pivotal mounting for said bar and a pair of grippers on opposite sides of said mounting for alternatively engaging said bar in said operative position and in a retracted position alongside said arm.

5. A trenchexcavator as defined in claim 3 wherein said drum is provided with a stationary apron supported by said arm and covering at least a lower part of said open rear surface.

6. At trench excavator as defined in claim 3 wherein said drum is provided with a cowl supported by said arm and overlying an upper reach of said belt while opening into the interior of said drum in a direction facing oncoming soil fragments entrained by said stop means.

7. A trench excavator as defined in claim 6 wherein said cowl is provided with scraper means for detaching the entrained soil fragments substantially at the zenith of the inner drum periphery.

8. A trench excavator as defined in claim 7 wherein said drum is provided with mechanism for retracting said stop means outwardly on the approach to said scraper means.

9. A trench excavator as defined in claim 8 wherein said stop means includes an elbow-shaped lever and said mechanism comprises stationary cam means supported on said arm and cam-follower means on said lever engageable with said cam means.

10. A trench excavator as defined in claim 1 wherein said cutler means comprises a plurality of angularly staggered strips of generally radial orientation provided with generally parallel slots at different distance from the drum axis, said cutter means including outwardly projecting blades overhanging said slots.

11. A trench excavator as defined in claim 1 wherein said drive means is operative to rotate said drum at a peripheral speed developing a centrifugal force substantially balancing the force of gravity at the zenith of the drum periphery. 

1. A trench excavator comprising: a vehicle movable in a predetermined direction, said vehicle being provided with a laterally extending outrigger arm; a drum journaled on a free end of said arm for rotation in a plane generally perpendicular to said direction, said drum having an apertured front surface externally provided with cutter means, an open rear surface and a substantially continuous peripheral zone between said surfaces; drive means for rotating said drum; conveyor means extending through said open rear surface into said drum for carrying off soil fragments; and retractable stop means on said peripheral zone radially movable between an inwardly projecting position for the rotary entrainment of soil fragments detached by said cutter means and an outwardly withdrawn position for releasing such soil fragments onto said conveyor means.
 2. A trench excavator as defined in claim 1 wherein the axis of said drum diverges forwardly from said direction at an acute angle of up to substantially 15* .
 3. A trench excavator as defined in claim 1 wherein said arm is provided with supporting means for said conveyor means, the latter including an endless belt extending to the rear of said vehicle at an acute angle to said arm in an operative position of said conveyor means.
 4. At trench excavator as defined in claim 3 wherein said conveyor means further comprises a roller-carrying bar enveloped by said belt, said supporting means including a pivotal mounting for said bar and a pair of grippers on opposite sides of said mounting for alternatively engaging said bar in said operative position and in a retracted position alongside said arm.
 5. A trench excavator as defined in claim 3 wherein said drum is provided with a stationary apron supported by said arm and covering at least a lower part of said open rear surface.
 6. At trench excavator as defined in claim 3 wherein said drum is provided with a cowl supported by said arm and overlying an upper reach of said belt while opening into the interior of said drum in a direction facing oncoming soil fragments entrained by said stop means.
 7. A trench excavator as defined in claim 6 wherein said cowl is provided with scraper means for detaching the entrained soil fragments substantially at the zenith of the inner drum periphery.
 8. A trench excavator as defined in claim 7 wherein said drum is provided with mechanism for retracting said stop means outwardly on the approach to said scraper means.
 9. A trench excavator as defined in claim 8 wherein said stop means includes an elbow-shaped lever and said mechanism comprises stationary cam means supported on said arm and cam-follower means on said lever engageable with said cam means.
 10. A trench excavator as defined in claim 1 wherein said cutler means comprises a plurality of angularly staggered strips of generally radial orientation provided with generally parallel slots at different distance from the drum axis, said cutter means including outwardly projecting blades overhanging said slots.
 11. A trench excavator as defined in claim 1 wherein said drive means is operative to rotate said drUm at a peripheral speed developing a centrifugal force substantially balancing the force of gravity at the zenith of the drum periphery. 